| 摘要 |
PURPOSE:To enable a delivery amount of a variable displacement pump to be controlled easily further with the plural characteristics, by providing a throttle or the like respectively in plural branch lines which branch to a tank from a control line connecting a control pump and the variable displacement pump. CONSTITUTION:An engine 1 connects a variable displacement pump 12 and a fixed displacement control pump 13 respectively being associated with the engine. And the pump 12 connects a vehicle running oil hydraulic motor 15 through each main line 16, 17. While the control pump 13 connects each cylinder 22, 23, which controls a tilt angle of a swash plate 21 in the pump 12, through each control line 26-28 having a selector valve 25 in the intermediate. Here a control device provides a branch line 41, which branches to a tank 38 from between a sequence valve 37 and the control pump 13 in the control line 26, and a throttle 39 in this branch line 41. While the device connects the control line 26 to a return line 46 through a branch line 53 having a sequence valve 51 and a variable throttle 52. |
